One of the most persistent and troublesome problems arising during modern fabric laundering operations is the tendency of some colored fabrics to release dye into the laundering solutions. The dye is then transferred onto other fabrics being washed therewith.
One way of overcoming this problem would be to bleach the fugitive dyes washed out of dyed fabrics before they have the opportunity to become attached to other articles in the wash.
Suspended or solubilized dyes can to some degree be oxidized in solution by employing known bleaching agents.
GB 2 101 167 describes a stable liquid bleaching composition containing a hydrogen peroxide precursor which is activated to yield hydrogen peroxide on dilution.
However it is important at the same time not to bleach the dyes actually remaining on the fabrics, that is, not to cause color damage.
U.S. Pat. No. 4,077,768 describes a process for inhibiting dye transfer by the use of an oxidizing bleaching agent together with a catalytic compound such as iron porphins.
Copending EP Patent Application 91202655.6 filed Oct. 9, 1991, relates to dye transfer inhibiting compositions comprising an enzymatic system capable of generating hydrogen peroxide and porphin catalysts.
It has now been found that certain amine base catalyst stabilizers when added to said enzymatic dye transfer inhibiting compositions enhances the overall performance of said compositions. The addition of said catalyst stabilizers reduces the rate of self-destruction of the porphin catalyst resulting in improved through-the-wash stability of the porphin catalyst. Also, improved whiteness benefits are obtained in the presence of catalyst stabilizers, due to a substantial reduction in the amount of porphin catalyst deposited onto the fabrics. Furthermore, it has been found that said catalyst stabilizers accelerate the oxidation reactivity of the porphin catalyst thereby increasing the rate of the dye bleaching.
Accordingly, a dye transfer inhibiting composition is provided which exhibits optimum dye transfer inhibiting properties.
According to another embodiment, the invention provides an efficient process for laundering operations involving colored fabrics.